Bituminous roadway



Patented June 5, 192a. i a I 1,572,408

. UNITED STATES PATENT OFFICE.

JOHN WESLEY FBAZIEB, SAN ANTONIO TE xAB, ASSIGNOB TO UVALDE BOCK A8- Pm! COMPANY, OF SAN ANTONIO, TEXAS.

BITUMINOUS ROADWAY.

liollrawing. Application filed April 15, 1984. Serial No. 708,741.

My invention relates to an improved screen. It is then run into the drum and method of constructing a base for roadways the drum rotated to thoroughly mix the having a topping of bituminous material coated mineral chips with .t e pulverized thereon. I rock asphalt. Thev temperature of the It is an object of the invention to provide charge is kept between 250 F. and 350 F. 56 a method of forming a base for roadways for good results and should not be allowed which is firm and compact and capable of to vary be ond these limits. J resisting the wear of traffic for long periods. 7 When t e charge is thoroughly heated My road base is adapted to support a biand mixed, it is discharged and distributed tuminous topping preferablymock asphalt upon the sub grade. It is raked into a 0 applied either hot or cold. smooth layer of the desired depth and rolled It is also desired to provide a roadway to solidly compact them'ixture upon the which is cheap to construct and economical roadway. "A surfacing of richer material to keep up. may be then added 'asdesired, referably It is particularly desired in the formation made u principally ofpulve'ri rock as- 65 I ofmy improvement to firmly bond the maphalt t oroughly rolled and compacted.

terials together so that they will not yield I find, when aroad surfacing is thus made under loads and thus become uneven and and treated, the bituminous bmderadheres rough. firmly to. the mineral articles so that the In carrying out my invention I' employ roadway. becomes a so n'd mass which will 70 the usual mineral aggregate, which may be not break :5 or crack. The bituminous graded from pieces about 1 inch in thickbinder is s cient tb make the "roadway ness to broken particles of stone and sand flexible under the strains of trafiic, temperaof size small enough topass through a ture, and severe weather conditions.

2 mesh screen. The material may be the usual The base thus formed is-commonl called crusher run of. stone with the addition of 'black base and when constructed in t e'mansand, it necessary, to furnish enough fine ner described, all the voids and interstices materials to fill the voids between the are filled. with rock asphalt and said rock larger particles. 1 asphalt is thoroughl rmeated withbitu- 30 The said mineral aggregate is run into men. The. rock aspha t is much more ef- 80 a drum, and heated thoroughly; and-an asfective inzproducing an efiicientbinder than 'phaltic base oil is'added in" the drum suf-f is eommon'asph'alt in that the limestone is ficient to thoroughly coat all the surface of ure and is thoroughly impregnated with the mineral particles. To accomplish this, t e heavy bitumen ina manner not possible the drum is rotated and theetemperaturmto attain by artificial means. When finely u those .w

maintained so as to make the oil easily fluid. ground it may be compacted to form a homo- The mineral particles when thus coated.. geneousmassfree of voids. adhere to the bituminous-binder employed The proportions of. materials may be so that all the constituents become firmly varied somewhat depending on conditions 40, bonded together. The asphaltic oil being of trafiic and the statev of the sub grade u on 00 less viscous, can form a film thoroughly imwhich the base is laid. I donot there ore pregnating all the particles. desire to be limited to the exact proportions Pulvcrized rock asphalt is then addedin andform of the constituent parts. i the proportion of about 10% to'15%'of the ,What I claim as new, and desire to pro- 45 mass.- Said rock asphalt is taken the tect by Letters Patent isz. form in whichit comes-from the quarry and LA process of forming bituminous road iisyrun through av rock crusher until-it'is base comprising the heating of crushed rock reducedto a fine powder, containing partiand mineral particles, coating the same-with cles.'ran ing from 4 inch in thickness to a thin film of asphaltic oil, mixi therefiich can pass through a 200 mesh with about 10% 0f the bulk in p' verized 1o eral aggregate, agitating the same and coating it with asphaltic oil, and mixing therewith about 10% of pulverized rock asphalt.

3. A process of forming bituminous roati base comprising coating a charge of crushed 10 mineral aggregate with asphalticoil, and

intimately mixing therewith about one tenthof the bulk in pulverized rock asphalt. p

In testimony whereof I hereunto afiix my signature this 5th day of April, A. D. 1924.

JOHNWESLEY FRAZIER. 

